Drawing die



Nov. 10, 1936. c. Q R|CHARD 2,060,690

DRAWING DIE Filed July 9, 1934 2 SheetsSheet l 9 /P INVENTOR.

ATTORNEY.

NOV. 10, 1936. c, c; RICHARD 2,060,690

' DRAWING DIE Filed July 9, 1934 2 Sheets-Sheet 2 INVENTOR.

' Cleflmfwi C'Fz'c%ard ATTORNEY.

Patented Nov. 10, 1936 UNITED STATES PATENT OFFIQE DRAWING DIEApplication July 9, 1934, Serial No. 734,284

5 Claims.

This invention relates to drawing dies for the forming of sheet metal,the object being to provide a male and a recessed female die part inwhich the male part is moved along a straight line to fit into thefemale portion of the die and in which the female portion of the die hasa throat or opening at its face less in distance across than thedistance across the recess below the opening.

The purpose of such a structure of die is for the formation of a sheetmetal part in which the formed metal has a curved portion of more than ahalf circle as for instance in the formation of an automobile fender.Such fenders at the present time are made generally of at least twoparts welded together and the exposed surface at least of the fender atthe welded point is, subsequent to welding, finished to provide auniform smooth surface for application of the enamel or lacquer finish.The object of this invention therefore is to provide a die structurecapable of forming a sheet metal article in which some portion thereofis turned to form more than a hemisphere and sometimes termed plus ahemisphere by the trade.

A feature of the invention is involved in the formation of the maleportion of the die of two parts, the entering portion of which ispivotally supported whereby in the moving of the male portion into thefemale portion of the die or Withdrawing the same therefrom, the saidpivoted portion may rock on an axis to turn into the recess to beneaththe overhang of the female die and of the metal to be formed thereinprior to the die parts being in seated relation with the metal and thatin the withdrawing movement the die will rock in an opposite directionfrom beneath the overhand to be drawn from the die on a straight line.In association with such die parts is provided a means for holding thepivoted portion of the male member in position to move in a straightline until it has reached a position to enable the same to be rocked onits pivot with the metal engaging surface thereof in proper relationshipwith the complemental surface of the female die.

A further object and feature of the invention is involved in the meanswhereby the pressure in forming an article is not applied to the pivotbut is taken by the body of the said pivoted element thus relieving thepivot of the strain incident to formation of the metal part.

These and other objects and various novel features of construction of adrawing die embody my invention are shown in the accompanying drawingsin which-- Fig. 1 is a longitudinal vertical section of a drawing dieembodying my invention in which the parts are shown in their finalrelationship in the forming of a sheet of metal.

Fig. 2 is a similar view showing the position of the pivoted maleportion of the die prior to its actually entering the female portiondie.

Fig. 3 is a section taken on line 3-3 of Fig. 1.

Fig. 4 is a section taken on line l-4 of Fig. 1 showing the form of thedie parts in cross section.

Fig. 5 is an elevation of a fender.

The embodiment of the invention shown in the accompanying drawings is adrawing die for the making of automobile fenders in which the curvedbase portion of the fender indicated at I in Fig. 5 terminates at 2 andthe distance between this terminal point 2 and the opposed point 3 ofthis base portion 1 of the fender is less than the distance across thefender on the dotted line a. The punch in forming the fender must passinto the female die in such position that the length thereof in theplane of the face of the fender the part is approximately equal to thedistance between the points 2 and 3 and after entering female die mustbe turned into the curved part at the forward end of the fender of theform here shown to underlie the point 2 and to practicallysimultaneously engage the metal throughout its length to properly formthe same, the skirt or flanges of the fender 4 being shaped by the dieparts as hereinafter mentioned.

This invention therefore seeks to provide a die construction in whichthe male portion or punch has a pivoted portion of its body so shapedthat when turned in one direction it may pass into the female die andthereafter be turned in the opposite direction to engage the portion ofthe die of greater length. Depending upon the shape of the article beingmade, the dies will of course be correspondingly shaped for theformation of various articles other than fenders here specificallydescribed in relation to the die parts shown.

The die shown is intended for use in a double acting press customarilyemployed in fender die work and not here particularly shown. The press,however, has what is known as the blank holder plate 5 attached to thehead 6 and to this plate is secured the upper holding ring I. The headand plate 5 and 6 are apertured to receive the driver 8 which isprovided at its lower face with an arcuate surface 9 recessed at itscenter to receive the head of a trunnion l 0. This trunnion has a pinIt) at its lower end approximately at the axis of the said arcuateportion 9. The pivoted portion of this punch structure is indicated atand has a triangular recess I2 opening through the arcuate face l3formed on the same axis as the face 9 of the driver.

The pin Ill extends into apertures indicated by dotted lines M in thebody of the pivoted element II to provide lost motion of the pin H inthe aperture I4. Thus as the punch member including this pivoted head Iis moved into the die part Hi to engagement with the metal, as is theposition of the parts in Fig. 1, the surface l3 is contacted by theconcentric surface 9 of the driver and the pressure in formation of thefender part is taken between these surfaces and not on the pin ID. Theupper die part is dual in character, it having the male punch elementformed of the parts 8 and H and the upper ring member 1 which has anopening l5 of the same length or diameter of the opening in the face ofthe lower ring or female die part l6 which is supported on a base |6*-.In operation the upper ring 1 is first moved downwardly to engage themetal I! prior to movement of the pivoted punch element I I by the arm 8into the female die. The upper ring I may be provided with a bead l8 tofit a complemental groove in the face of the female element I6 wherebyas the upper ring I is moved to the position shown in Fig. 2, the sheetmetal blank I! is clamped at its opposite ends to hold the sheet duringthe drawing operation. The relationship of the die parts is such thatwhen the punch is withdrawn, the face portion of the pivoted die part IIlies in the opening l5 of the upper ring 1 and as the wall of thisopening is of sufficient length that, in its movement in respect to thepivoted punch part I the heel IQ of the die part II lies against thiswall of the aperture l5 and the portion H, as shown in Fig. 2, is swungto the right of the position of the part shown in Fig. 1.

The die part II however is not free to swing on the pivot pin but isactuated and held in its pivotal movement by cams 20 and 2| as shown inthe section Fig. 3 and a similar pair of cams, one of which is indicatedat 22 in Fig. 2 on the opposite side of the die part II to which thesecam elements are secured as by means of bolts 23. These cams extendupwardly from the female die part I6 through apertures provided in thebase of the upper ring I to the interior of the ring which is formedwith a recess 24 into which they extend on opposite sides of the driverelement 8 of the punch. The members of each pair of cams, as 20 and 2|of Fig. 3, are on opposite sides of the driver element 8 and in opposedrelation with the other pair of cams one of which is indicated at 22 inFig. l. The cams 20 and 2| as shown in Fig. 1 have cam faces 25 and thecam members 22 have oppositely inclined faces 26 as shown in Fig. 1 andin both cases the pairs of cams on one side of the driver at the leftside of Fig. 1 have inclined faces oppositely disposed in practicallyparallel relation with the inclined faces 26 of the cams on the rightside of Fig. 1. Between the cam 28 and 22 and 2| and its opposedcompanion member 22 extend the actuating bars 21 and 28 as will beunderstood from Fig. 3 and the upper ring also has a pair of brackets 29on each side for the purpose of strengthening the side walls of theupper ring. The driver 8 has an elongated part 30 on one side and 3| onthe other side as shown in Fig. 3 which are formed with a way to receivethese actuating bars and the ends 0 0h? bars are rounded as shown inFig. 1 and respectively engage the cam faces 25 and 26.

A plate 32 is provided on the side of the members 3B and 3| to hold eachbar in its way in which it is slidable. Each bar also has a pin 33approximately centrally disposed between the ends thereof, as indicatedmore clearly in Fig. 4, which extends into vertically elongatedapertures 34 in the pivoted punch element H on opposite sides of therecess l2 therein. The driver 8 is attached to the punch press by meansof an interposed element 35 and by which the driver 8 is movedvertically in the position of the parts shown. As the punch moves fromthe position shown in Fig. 2 to the position shown in Fig. l, theactuating bars 21 and 28 engage the respective cam faces and move thebars from the position shown in Fig. 1 and thus rocks the punch elementII on its pivot. The cams and the bars are so positioned that, as thepunch element moves from the position shown in Fig. 2 it is moved in astraight line into the opening of the female die portion l6 and as theheel portion IS of the punch element passes out of the upper ring 1 theends of the actuating bars engage the cams and rock the member II on itspivot H] to the left of the position shown in Fig. 2. As this movementproceeds the punch element II is turned to the position shown in Fig. 1just prior to the actual formation of the article and as this punchelement comes to the position stated the arcuate surface I3 is inengagement with the arcuate portion 9 of the driver 8 so that the finalforming pressure is taken on the end of the member H and not on the pindue to the lost motion heretofore mentioned of the pin H) in itsaperture in the part Thus the final metal forming movement of the punchpart is in a vertical line and the metal is engaged to an equal degreethroughout its surface between the die faces whereby the drawing of themetal is uniform.

A stop element 36 is provided in the recess of the member H to limit theturning thereof on the pivot Ill to too great a degree, it being desiredto hold the heel IQ of the member II in contact with the wall of theaperture |5 in the upper ring 8 to thereby properly enter the female diel6.

Upon upward movement of the driver in withdrawal of the member H fromthe female die portion l6 there is a straight line movement of thedriver to which the bars 2'! and 28 are slidably secured and due to theends of the bars engaging the inclined surface 25 of the cam elements 20and 2| on one side the bars are moved to the right of the position shownin Fig. 1 practically to the position shown in Fig. 2 which turns themember H on its pivot Ill permitting it to be withdrawn from theoverlying portion of the female die to within the recess defined by thewall of the apertures IS in the upper ring I. Thereafter the upper ring1 is moved upwardly to permit removal of the formed part andintroduction of a new part whereupon the forming movement of the partsas above described is repeated. The face of the element in cross sectionand likewise the female die is shown in Fig. 4 being of the form for themaking of a fender with its side flanges but, as previously stated, thedie while here shown as of a form for making a fender may be of a shapeto form any desired part. This form of die is of great value where theformed part has a portion thereof so overlying the body as to make itdifiicult or impossible to introduce a solid punch or one piece directlyinto the female die portion. In my invention the punch in most instancesis supported on a pivot extending at a right angle to the plane of theportion having the overlying or recurved part.

From the foregoing description, it will be evident that the describedinvention is adaptable for use in the making of sheet metal partsWherein the article formed has one portion overlying another portion tosuch extent that it is impracticable to move a solid punch into a femaledie part for the forming operation; that by the construction described,I have provided a drawing die in which the two die parts have a relativestraight line movement in the forming and withdrawing movements of themale portion of the punch and yet that may be turned to position toproperly form an overlying part simultaneously with the formation of thebody or remaining portion of the article being formed without submittingany part of the metal to sliding contact with a die part, and that thevarious objects and features of the invention are secured by theconstruction described, it being understood, however, that variouschanges in the form of the various parts may be made without departingfrom the spirit and scope of the invention as set forth in the appendedclaims.

Having thus briefly described my invention, what I claim and desire tosecure by Letters Patent of the United States isl. A drawing die,comprising male and female die parts, the said female die having arecess undercut on one side and the male die having a complementalprojection on one side, a holding means for supporting a piece of metalrelative to the female die for the shaping operation, said holding meanshaving an aperture therethrough aligned with the male die part andthrough which the said die part is movable into the female die, said mae die part being formed of two members, one movable in a fixed line andthe other a terminal die part pivoted to the first named part, the saidholding means being movable to engage the metal to be formed prior tomovement of the male die part into the female die part, the said firstnamed part of the male die and the pivoted portion having concentricsurfaces, the pivotal support being formed with sufficient lost motionas to permit the concentric surfaces to come into pressure contact inthe formation of the article to relieve the pivot point of strain, andmeans automatically operating to turn the said pivoted part of the maledie as it enters the female portion of the die to position theprojection in the undercut portion of the female die as the die facesapproach para lel relation, the said automatic means further automatically operating to turn the said pivoted portion of the male diepart in the opposite direction as the male die is withdrawn aftercompletion of the forming operation.

2. In a drawing die, a stationary female die and a movable male die,said male die having a terminal end portion of a shape complemental tothe shape of the recess of the female die and a reciprocable portion towhich the terminal portion is pivoted, the female die part having arecess of greater distance fro-m side to side below the surface than atthe surface providing an overhang and the pivoted member having aprojecting portion to be moved thereinto in the forming of a sheet ofmetal, stationary cam members on opposite sides of the female dieelement, a sliding bar on the reciprocable portion of the male dieelement, the respective ends of which engage the opposed cam elements,said bar having a pivotal connection with the pivoted die and said camsof such form that in movement of the male die toward the female die, thecams turn the pivoted die part as it enters the female die to positionthe said forming surface of the die in substantially parallel relationwith the female die and on movement in the opposite direction the camsoperate the bar to turn the pivoted die element in an opposite directionto withdraw the same from the female die.

3. In a drawing die for the purpose described, a female die having arecess opening through its face and a male die portion having a pivotedpart of a shape corresponding to the female die recess and movablethereinto, a pair of stationary cams positioned at opposite sides of thefemale die and extending upwardly therefrom, a bar slidably supported bythe male die, the ends thereof engaging the respective cams providing ameans for turning the pivoted portion of the male die in one directionon the forming stroke and in the opposite direction on the Withdrawingmovement, and a holding ring movable in timed relation with the movementof the male die for engaging and holding a sheet of metal over therecess of the female die prior to engagement of the pivoted die membertherewith.

4. In a drawing die, a female die part having a recess undercutting theface of the die providing an inturned flange on one side, a male diepart comprising a reciprocable element and a pivoted part provided witha projection on one side to engage the said undercut portion of thefemale die and of a shape otherwise complemental to the female die, saidpivoted part having a curved surface whose axis coincides with the axisof the pivoted part and the other part of the male die portion having aconcentric curved surface, the pivotal connection being of aconstruction to provide sufficient for lost motion to permit theconcentric surfaces to come to engagement in the forming of the article,and means for automatically causing said pivoted part of the male die toturn as it enters the recess of the female die to engage said undercutportion and to automatically turn in an opposite direction onwithdrawal.

5. In a drawing die, a female die part and a male die part, the femaledie part having a recess undercutting the face of the die providing aninturned flange on one side and the male die comprising a reciprocableelement and a pivoted part provided with a projection on one side toengage the said undercut portion and of shape otherwise complemental tothe female die recess, and a stationary cam means for causing thepivoted portion of the male die to turn as it enters the recess of thefemale die to engage in the undercut portion and to turn in an oppositedirection on withdrawal.

CLEMENT C. RICHARD.

